Chapter 7.12, Problem 43CC

(a)

Interpretation Introduction

Interpretation:

The plausible mechanism for the given reaction has to be drawn.

Concept Introduction

Unimolecular nucleophilic substitution reaction$\left({\text{S}}_{\text{N}}1\right)$: Reaction of alkyl halide with nucleophile involves two step processes,

• Loss of leaving group: where the loss of leaving group from the substrate gives a carbocation intermediate.
• Nucleophilic attack: A nucleophile attacks the carbocation intermediate to afford the product.

Stability of carbocation: Generally $\left({\text{S}}_{\text{N}}1\right)$ process are observed for tertiary alkyl halides; the stability of carbocation as follows,

${\text{3}}^{\text{o}}\text{Carbocation}\text{>}\text{benzylic}\text{cation}\text{=}\text{allyl}\text{cation}\text{>}{\text{2}}^{\text{o}}\text{cation}\text{>}{\text{1}}^{\text{o}}\text{cation}\text{>}\text{methyl}\text{>}\text{vinylcation}$

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: Donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

(b)

Interpretation Introduction

Interpretation:

The plausible mechanism for the given reaction has to be drawn.

Concept Introduction:

Elimination reaction: A general reaction type in which a substance X-Y lost to yield unsaturated product that has multiple bonds.

Zaitsev Rule: In an elimination reaction, the most substituted product is formed and is the most stable and favored product.

Hofmann rule: The major alkene product obtained in an elimination reaction is the least substituted and generally be the least stable. The process is based on the base been used.

Stability of carbocation: Generally $\left({\text{S}}_{\text{N}}1\right)$ process are observed for tertiary alkyl halides; the stability of carbocation as follows,

${\text{3}}^{\text{o}}\text{Carbocation}\text{>}\text{benzylic}\text{cation}\text{=}\text{allyl}\text{cation}\text{>}{\text{2}}^{\text{o}}\text{cation}\text{>}{\text{1}}^{\text{o}}\text{cation}\text{>}\text{methyl}\text{>}\text{vinylcation}$

Leaving group: It is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: Donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

(c)

Interpretation Introduction

Interpretation:

The plausible mechanism for the given reaction has to be drawn.

Concept Introduction:

Unimolecular nucleophilic substitution reaction$\left({\text{S}}_{\text{N}}1\right)$: Reaction of alkyl halide with nucleophile involves two step processes,

• Loss of leaving group: where the loss of leaving group from the substrate gives a carbocation intermediate.
• Nucleophilic attack: A nucleophile attacks the carbocation intermediate to afford the product.

Stability of carbocation: Generally $\left({\text{S}}_{\text{N}}1\right)$ process are observed for tertiary alkyl halides; the stability of carbocation as follows,

${\text{3}}^{\text{o}}\text{Carbocation}\text{>}\text{benzylic}\text{cation}\text{=}\text{allyl}\text{cation}\text{>}{\text{2}}^{\text{o}}\text{cation}\text{>}{\text{1}}^{\text{o}}\text{cation}\text{>}\text{methyl}\text{>}\text{vinylcation}$

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: Donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.

(d)

Interpretation Introduction

Interpretation:

The plausible mechanism for the given reaction has to be drawn.

Concept Introduction:

Elimination reaction: A general reaction type in which a substance X-Y lost to yield unsaturated product that has multiple bonds.

Zaitsev Rule: In an elimination reaction, the most substituted product is formed and is the most stable and favored product.

Hofmann rule: The major alkene product obtained in an elimination reaction is the least substituted and generally be the least stable. The process is based on the base been used.

Stability of carbocation: Generally $\left({\text{S}}_{\text{N}}1\right)$ process are observed for tertiary alkyl halides; the stability of carbocation as follows,

${\text{3}}^{\text{o}}\text{Carbocation}\text{>}\text{benzylic}\text{cation}\text{=}\text{allyl}\text{cation}\text{>}{\text{2}}^{\text{o}}\text{cation}\text{>}{\text{1}}^{\text{o}}\text{cation}\text{>}\text{methyl}\text{>}\text{vinylcation}$

Leaving group: it is a fragment that leaves substrate with a pair of electrons via heterolytic bond cleavage.

Nucleophile: Donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.